What is produced by the dissociation of an electrolyte in an aqueous solution?

When an aqueous solution of sodium sulfate $(Na_2SO_4)$ is electrolyzed,what are the products obtained at the cathode and anode,respectively?

The incorrect statement about the Castner-Kellner cell process is

Which of the following solutions,upon electrolysis,produces $H_2$ gas at the cathode and $Cl_2$ gas at the anode?

Assertion : $A$ small amount of acid or alkali is added before electrolysis of water.
Reason : Pure water is a weak electrolyte.

The product obtained at the anode on electrolysis of aqueous $H_2SO_4$ in the presence of $Pt$ electrodes is: